As has already been stated, there is no "magic scale" that will work in every situation. The Astrodon LRGB Gen II filters are supposed to be 1:1:1 for either Kodak or Interline sensors. Even though the filters may be 1:1:1, it doesn't mean that what you are actually capturing is correct!
That may sound strange but depending on where it is in the sky at the time changes the colour slightly (near horizon or zenith), imaging on different nights and seeing conditions, water vapour or dust in the atmosphere. Of course there is also dust between us and what we're imaging!
PI has some great tools for colour calibration, mostly I guess you just need to be selective about what you are using as your calibration. One good way to go, Aladin Sky Atlas!
http://aladin.u-strasbg.fr
That way you can manually align flux values in RGB (well actually Johnson-Cousins Photometric UBVRI)
